The role of neuronal NO synthase in the respiratory effects of TNF-α

It was shown that an increase level of proinflammatory cytokines has a modulating effect on the reflex control of respiration. The aim of this study was to investigate the involvement of neuronal nitric oxide synthase (nNOS) in the mechanisms of the influence of an increased level of Tumor necrosis factor – α (TNF-α) on the hypoxic ventilatory response. To achieve this goal, experiments were carried out on urethane anesthetized rats with intravenous administration of TNF-α before and after pretreatment with 7-nitroindazole specific nNOS inhibitor. The hypoxic ventilation response was assessed by rebreathing with a hypoxic gas mixture before and after administration of TNF-α. We found that TNF-α decreased the ventilatory response to hypoxia. Pretreatment with nNOS inhibitor reduced respiratory effects of TNF-α. Key words: cytokines, TNF-α, hypoxia, chemoreflex, respiration, ventilation, neuronal nitric oxide synthase.